“I am writing to let you know that treating customers in that way will only cost you more in the long term.”

The R2-D2 high heels that Rayner missed out on

The chain’s head of retail, Daniel Theophanides, said that Rayner sent two letters, one to head office and the other to the firm’s Brighton outlet.

He said that he was “very shocked” at the wording of the letter, adding that it “wasn’t nice, it was cruel”.

Theophanides said that Rayner had mistakenly believed she was on a pre-order list, when in fact customers had to buy them in person from the company’s shops.

Angela Rayner, MP for Ashton-Under-Lyne

He added that he called her to say that he was sorry she had missed out on the chance to buy the heels but claimed that she “hung up” before he had a chance to offer her a pair he had sourced from China.

The MEN reported that she tweeted about the incident - although she now appears to have deleted her Twitter account.

She told the publication that she had been complaining about the “poor level of customer service”.